FIG. 2.

KSHV-enhanced HUVEC invasiveness is MMP dependent and is mediated by a paracrine mechanism. (A) KSHV-induced cell invasion was MMP dependent. A specific inhibitor of MMPs, BB-94, abolished KSHV-increased cell invasiveness. (B) KSHV infection increased paracrine-dependent cell invasion. Virion-free supernatants from mock- or KSHV-infected HUVEC cultures (Medium_Mock and Medium_KSHV, respectively) were assayed for their abilities to promote cell invasion of normal HUVEC with or without the presence of the inhibitor of MMPs, BB-94. The invasion assays were carried out as described for Fig. 1. HUVEC that had invaded the Matrigel layer were quantified in two independent experiments, each with three to four repeats. The total number of repeats (n) for each condition is shown in the figures. Each dot represents the average number of cells per microscopic field in one test well in the invasion assay. The bars and their associated numbers are the average numbers of invaded cells per field from all the wells under different test conditions. P values shown are from a two-tailed Fisher's exact test.